x86/HVM: 32-bit IN result must be zero-extended to 64 bits (part 2)

Just spotted a counterpart of what commit 9d89100b (same title) dealt
with.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Keir Fraser <keir@xen.org>

diff --git a/xen/arch/x86/hvm/io.c b/xen/arch/x86/hvm/io.c
index deb7b92fdca3ca594f80316e6b448c6f71fdbde2..15e0b4c0ae0545e4b3ce6fe2c3776fcdb298d2de 100644 (file)
--- a/xen/arch/x86/hvm/io.c
+++ b/xen/arch/x86/hvm/io.c
@@ -290,8 +290,10 @@ void hvm_io_assist(ioreq_t *p)
         (void)handle_mmio();
         break;
     case HVMIO_handle_pio_awaiting_completion:
-        memcpy(&guest_cpu_user_regs()->eax,
-               &p->data, vio->io_size);
+        if ( vio->io_size == 4 ) /* Needs zero extension. */
+            guest_cpu_user_regs()->rax = (uint32_t)p->data;
+        else
+            memcpy(&guest_cpu_user_regs()->rax, &p->data, vio->io_size);
         break;
     default:
         break;